What this MCCB is and what it does
The Siemens 3VA2225-5KP32-0KL0 is a SENTRON molded case circuit breaker (MCCB) rated for 250 A continuous current, built for line protection in industrial and commercial power distribution panels. It carries a 187 kA interrupting capacity at 240 V AC — enough to clear high-fault bolted faults on the secondary side of a large transformer without upstream coordination headaches. The ETU850 electronic trip unit gives you adjustable long-time, short-time, instantaneous, and ground-fault protection curves, so you can shape selectivity with downstream breakers rather than oversizing the whole feeder. Three poles, 800 V rated insulation voltage, and a maximum power loss of 48 W at rated current — that 48 W matters for enclosure heat rise if you pack several breakers in a single cabinet. The operating temperature range runs from -25 °C to 70 °C, with storage from -40 °C to 80 °C, so it handles unconditioned electrical rooms and seasonal temperature swings.
Interrupting capacity and derating — what the numbers mean for your panel
The interrupting ratings step down with system voltage: 187 kA at 240 V, 121 kA at 415 V and 440 V, 79 kA at 500 V, and 5.1 kA at 690 V. That 5.1 kA at 690 V is the weak point — if your 690 V bus has a higher available fault current, you need a different frame or a current-limiting upstream device. The 250 A continuous rating holds flat from 40 °C through 50 °C, then derates to 238 A at 55 °C, 225 A at 60 °C, 213 A at 65 °C, and 200 A at 70 °C. Mounting in a warm enclosure without forced ventilation means you plan for the derated number, not the nameplate. Dimensions are 105 mm wide, 181 mm high, 86 mm deep — the width is the critical panel cutout dimension for a 3-pole MCCB. The auxiliary contact configuration is 2 auxiliary switches + 1 trip alarm switch + 1 electrical alarm switch (HQ type), plus a shunt trip release (STL) for remote tripping. The undervoltage release is not fitted on this variant.